A liquid crystal display device is provided with a TFT substrate including a pixel electrode and a thin film transistor (TFT) in a matrix form and an opposing substrate opposing the TFT substrate and formed thereon with a color filter or the like in a position corresponding to the pixel electrode of the TFT substrate, and liquid crystal is sandwiched between the TFT substrate and the opposing substrate. The device forms an image by controlling a light transmission of a liquid crystal molecule with respect to each pixel.
For such a liquid crystal display device, there is a demand for reducing an external size of the set while retaining a certain size of a screen as well as for reducing a thickness of the liquid crystal display panel. However, reduction in the thickness of the liquid crystal display panel may lead to a problem of its bending strength. Especially, a system of controlling a display on a screen by pressing a finger or the like on a touch panel has been increasingly used in recent years. In such a system, the bending stress is applied to the liquid crystal display panel through the touch panel.
When the bending stress is applied to the liquid crystal display panel, if there is a chip of glass or the like at an edge of the TFT substrate or the opposing substrate which are glass substrates, the glass may break from that point. In order to prevent this, the edge of the glass substrate is chamfered off. However, chamfering off alone cannot necessarily provide a glass substrate with reliably high bending strength.
Japanese Unexamined Patent Application Publication No. 2011-84453 describes a configuration of a chamfered glass substrate with an inclination root mean square of a roughness curve of the chamfered surface RAq being 0.1 or less to prevent a crack of the glass when a flexure is caused in the glass substrate. Japanese Unexamined Patent Application Publication No. 2008-266046 describes a configuration of a glass substrate having its edge chamfered off with the chamfering size being 18 to 75 μm in a direction of the substrate thickness to make it difficult for a crack to be caused in the glass substrate.